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Commit 62874c3a authored by Kees Cook's avatar Kees Cook
Browse files

selinux: Refactor to remove bprm_secureexec hook 



The SELinux bprm_secureexec hook can be merged with the bprm_set_creds
hook since it's dealing with the same information, and all of the details
are finalized during the first call to the bprm_set_creds hook via
prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored
via bprm->called_set_creds).

Here, the test can just happen at the end of the bprm_set_creds hook,
and the bprm_secureexec hook can be dropped.

Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarPaul Moore <paul@paul-moore.com>
Tested-by: default avatarPaul Moore <paul@paul-moore.com>
Acked-by: default avatarSerge Hallyn <serge@hallyn.com>
Reviewed-by: default avatarJames Morris <james.l.morris@oracle.com>
Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
parent 993b3ab0

security/selinux/hooks.c

+5 −19
Original line number Diff line number Diff line
@@ -2442,30 +2442,17 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) 


		/* Clear any possibly unsafe personality bits on exec: */

		bprm->per_clear |= PER_CLEAR_ON_SETID;

	}



	return 0;

}



static int selinux_bprm_secureexec(struct linux_binprm *bprm)

{

	const struct task_security_struct *tsec = current_security();

	u32 sid, osid;

	int atsecure = 0;



	sid = tsec->sid;

	osid = tsec->osid;



	if (osid != sid) {

		/* Enable secure mode for SIDs transitions unless

		   the noatsecure permission is granted between

		   the two SIDs, i.e. ahp returns 0. */

		atsecure = avc_has_perm(osid, sid,

					SECCLASS_PROCESS,

					PROCESS__NOATSECURE, NULL);

		rc = avc_has_perm(old_tsec->sid, new_tsec->sid,

				  SECCLASS_PROCESS, PROCESS__NOATSECURE,

				  NULL);

		bprm->secureexec |= !!rc;

	}



	return !!atsecure;

	return 0;

}



static int match_file(const void *p, struct file *file, unsigned fd)
@@ -6266,7 +6253,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { 
	LSM_HOOK_INIT(bprm_set_creds, selinux_bprm_set_creds),

	LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds),

	LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),

	LSM_HOOK_INIT(bprm_secureexec, selinux_bprm_secureexec),



	LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),

	LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),